Excess heat in the aquarium can have several causes that the hobbyist can possibly eliminate without incurring great expenses, usually buying a cooling unit.

A few that are easy to solve, or at least less expensive to solve than buying a cooler are:

• Determine whether the pumps you are using are the cause for the excessive heat. Submersible pumps are always suspect. Indeed, they cool down by transferring heat to the water. Power head pumps do the same. Too large a submersible pump, or too many power heads will raise the temperature several degrees, perhaps several too many. Use only pumps that run cool and do not exchange heat with the water. Blast cooled pumps are your best bet.
• Lights that are not equipped with internal fans, or that are placed too close to the water, will heat up the water, possibly by several degrees.
• Heat transfers to the water from the surrounding air. If the room in which the aquarium is placed is very hot, the tank's temperature will rise.
• Heat transfers to the water from the inside of the cabinet where you placed your trickle filter, or from the cellar if that is where yours is. Watch the ambient temperature in both of those areas.

If you cannot solve your temperature problem by changing pumps, or by installing fans in the lighting hoods, you may be in a quandary that can only be resolved by installing a cooling unit.

Cooling units cost from $500.00 to several hundreds more, depending on size, and because they are compressor operated, consume a fair amount of electricity as well. Try to solve your problem otherwise if you can.

Many hobbyists do not have a heat problem and need to provide supplemental heating to their tank. Such is easily done by installing one or more bayonet heaters in the sump of the trickle filter, depending on how much heat needs to be generated.

Because bayonet heaters can stick, meaning stay in the on position, I always recommend the use of several, rather than just one, especially if you need a fair amount of heating. For example, I would use three 50 watt heaters, rather than one 150 watt. Since it is unlikely that all three will fail at the same time, and since 50 watts cannot do as much damage as one 150 watt heater, I find such much safer.

Bayonet heaters, also called stick heaters, come in various finishes: plain glass tubes, glass covered with silicone, glass covered with a protective cover, ceramic, Teflon*, stainless steel, and so on. Your budget determines which one you get. I prefer the Teflon coated ones because they cannot break in the sump, but they cost a great deal more. So do the stainless steel ones.

If the heater you acquire does not have a built-in temperature on/off regulator, you will have to install a separate one to allow you to adjust the set point. Temperature controllers, similar to the units existing for pH and redox, are also available from certain resellers and from the catalog companies already mentioned.

When it comes to heaters, accuracy in the on and off switching is key. Such is also the reason you should buy a well known brand, not some cheap knock-off. You have too much at stake. Don't let an extra $20.00 for a good quality heater endanger the life of the animals in your tank. Believe me, cheap heaters will stick.

Besides using Teflon units, I also like the German Ebo-Jaeger units a lot because they are submersible, adjustable, accurate, and covered with a protective layer so the glass is not easily shattered.

Cable heating is yet another and a more stable form of heating and mainly so because it spreads the heat much more evenly throughout the tank. Unfortunately the cables rip easily because of rocks and bully fish, urchins and so on. At Thiel*Aqua*Tech we are working on the development of such a system that holds up better in reef and freshwater plant tanks. Unfortunately it is not ready, and no date for its introduction is available at this time.

Rather inexpensive coolers can be made using a small second hand freezer. Many hobbyists have tried it and they work fairly well. One can reduce the temperature about 4-5 degrees if the system is properly set up, and if metal type tubing is used to conduct the water in and out of the freezer.

You must run water very slowly through a small diameter tube that enters the freezer somewhere through a hole you have to drill through its side. A coil on the inside ensures that the water remains inside for a certain amount of time. The longer the coil, and the slower you flow the water, the better cooling effect you will get.

Another hole needs to be drilled through the side for the tube to exit again. Water is pumped through the tube by means of a very small pump, maybe even a small power head pump. Alternatively, use water from a bypass on the main water return line, the one going back to the aquarium. This will require that you glue a Tee-fitting in-line, and then bush it down to the size of the tube (hose) that you are using. After you have passed the coil through the holes you drilled, isolate the inside of the unit by applying a liberal amount of aquarium silicone around the holes, both inside and outside the freezer.

Because certain types of material inhibit heat exchanges, e.g. plastics, the best cooling effect is obtained with stainless steel tubing. You must use 316 SS, as other types will not resist salt water for very long. Copper can, of course, not be used. Another metal that is safe, but much more expensive, is titanium.

The best way to cool the tank if the temperature is too high, is to use a chiller or cooling unit matched to the size of your tank, and the number of degrees you want to lower the water temperature.

Cooling units are fairly expensive by hobby standards, but if you absolutely need one few alternatives exist as we have already seen. Several companies now offer such equipment and advertise in magazines such as FAMA: Aquanetics, Aquarium Sales and Service and TAT. Call around before buying. Prices can vary quite a bit.

Investigate all other avenues open to you first, and if none bring the temperature down enough, consider getting a cooler if you are really interested in making your tank look much better, because it will make a big difference.

Whichever way you go, keeping the tank at the recommended temperature is yet another important aspect that you have to attend to. Trying to run the tank at far too high a temperature will not work, and will end up costing you more money in the long run anyway, not to speak of all the animals that will have been killed in the process.

NetPets® Main Page

contact information Main Reference Library

The Fish Center